1. Field of the Invention
The present invention relates to channel estimation and physical layer measurement and, more particularly, to a method of adaptively using a single estimator over time resources according to an object to be estimated and measured when channel estimation and physical layer measurement are performed in downlink.
2. Discussion of the Related Art
An LTE-Advanced system supports a machine type communication (MTC) terminal capable of transmitting information necessary for managing the system between apparatuses configuring the system, for applications such as smart metering, health care, security, transport and logistics, and environmental monitoring. The MTC terminal is characterized in that a low data transfer rate is supported for the purpose of management and monitoring and a large number of terminals may operate in one cell. Accordingly, the MTC terminal is preferably implemented in a low-level, low-cost terminal and, at this time, a method of simplifying an estimation and measurement operation performed by an MTC terminal may be considered.
In general, physical layer measurement of an LTE system is roughly divided into two methods: an intra-frequency measurement method and an inter-frequency measurement method. Information about the measurement method is determined by an eNB and may be sent to a user equipment (UE) via a broadcast control channel or a dedicated control channel. For example, the UE follows a measurement method defined for cell selection in a broadcast control signal in an RRC_IDLE state and follows a measurement method defined by an RRC signal which is a dedicated control signal transmitted from the eNB in an RRC_connected state.
Since an estimation or measurement element which may be included in a low-level low-cost terminal such as an MTC terminal is also restricted, there is a need for a method of adaptively performing estimation or measurement using the restricted estimation or measurement element.